@@ -41,6 +41,7 @@ type JSONFileLogger struct {

 	ctx          logger.Context

 	readers      map[*logger.LogWatcher]struct{} // stores the active log followers

 	notifyRotate *pubsub.Publisher

+	extra        []byte // json-encoded extra attributes

 }

 func init() {

@@ -77,6 +78,16 @@ func New(ctx logger.Context) (logger.Logger, error) {

 			return nil, fmt.Errorf("max-file cannot be less than 1")

 		}

 	}

+

+	var extra []byte

+	if attrs := ctx.ExtraAttributes(nil); len(attrs) > 0 {

+		var err error

+		extra, err = json.Marshal(attrs)

+		if err != nil {

+			return nil, err

+		}

+	}

+

 	return &JSONFileLogger{

 		f:            log,

 		buf:          bytes.NewBuffer(nil),

@@ -85,6 +96,7 @@ func New(ctx logger.Context) (logger.Logger, error) {

 		n:            maxFiles,

 		readers:      make(map[*logger.LogWatcher]struct{}),

 		notifyRotate: pubsub.NewPublisher(0, 1),

+		extra:        extra,

 	}, nil

 }

@@ -97,7 +109,12 @@ func (l *JSONFileLogger) Log(msg *logger.Message) error {

 	if err != nil {

 		return err

 	}

-	err = (&jsonlog.JSONLogs{Log: append(msg.Line, '\n'), Stream: msg.Source, Created: timestamp}).MarshalJSONBuf(l.buf)

+	err = (&jsonlog.JSONLogs{

+		Log:      append(msg.Line, '\n'),

+		Stream:   msg.Source,

+		Created:  timestamp,

+		RawAttrs: l.extra,

+	}).MarshalJSONBuf(l.buf)

 	if err != nil {

 		return err

 	}

@@ -181,6 +198,8 @@ func ValidateLogOpt(cfg map[string]string) error {

 		switch key {

 		case "max-file":

 		case "max-size":

+		case "labels":

+		case "env":

 		default:

 			return fmt.Errorf("unknown log opt '%s' for json-file log driver", key)

 		}

@@ -1,9 +1,11 @@

 package jsonfilelog

 import (

+	"encoding/json"

 	"io/ioutil"

 	"os"

 	"path/filepath"

+	"reflect"

 	"strconv"

 	"testing"

 	"time"

@@ -149,3 +151,51 @@ func TestJSONFileLoggerWithOpts(t *testing.T) {

 	}

 }

+

+func TestJSONFileLoggerWithLabelsEnv(t *testing.T) {

+	cid := "a7317399f3f857173c6179d44823594f8294678dea9999662e5c625b5a1c7657"

+	tmp, err := ioutil.TempDir("", "docker-logger-")

+	if err != nil {

+		t.Fatal(err)

+	}

+	defer os.RemoveAll(tmp)

+	filename := filepath.Join(tmp, "container.log")

+	config := map[string]string{"labels": "rack,dc", "env": "environ,debug,ssl"}

+	l, err := New(logger.Context{

+		ContainerID:     cid,

+		LogPath:         filename,

+		Config:          config,

+		ContainerLabels: map[string]string{"rack": "101", "dc": "lhr"},

+		ContainerEnv:    []string{"environ=production", "debug=false", "port=10001", "ssl=true"},

+	})

+	if err != nil {

+		t.Fatal(err)

+	}

+	defer l.Close()

+	if err := l.Log(&logger.Message{ContainerID: cid, Line: []byte("line"), Source: "src1"}); err != nil {

+		t.Fatal(err)

+	}

+	res, err := ioutil.ReadFile(filename)

+	if err != nil {

+		t.Fatal(err)

+	}

+

+	var jsonLog jsonlog.JSONLogs

+	if err := json.Unmarshal(res, &jsonLog); err != nil {

+		t.Fatal(err)

+	}

+	extra := make(map[string]string)

+	if err := json.Unmarshal(jsonLog.RawAttrs, &extra); err != nil {

+		t.Fatal(err)

+	}

+	expected := map[string]string{

+		"rack":    "101",

+		"dc":      "lhr",

+		"environ": "production",

+		"debug":   "false",

+		"ssl":     "true",

+	}

+	if !reflect.DeepEqual(extra, expected) {

+		t.Fatalf("Wrong log attrs: %q, expected %q", extra, expected)

+	}

+}

@@ -2,6 +2,7 @@ package jsonlog

 import (

 	"bytes"

+	"encoding/json"

 	"unicode/utf8"

 )

@@ -12,6 +13,9 @@ type JSONLogs struct {

 	Log     []byte `json:"log,omitempty"`

 	Stream  string `json:"stream,omitempty"`

 	Created string `json:"time"`

+

+	// json-encoded bytes

+	RawAttrs json.RawMessage `json:"attrs,omitempty"`

 }

 // MarshalJSONBuf is based on the same method from JSONLog

@@ -34,6 +38,15 @@ func (mj *JSONLogs) MarshalJSONBuf(buf *bytes.Buffer) error {

 		buf.WriteString(`"stream":`)

 		ffjsonWriteJSONString(buf, mj.Stream)

 	}

+	if len(mj.RawAttrs) > 0 {

+		if first == true {

+			first = false

+		} else {

+			buf.WriteString(`,`)

+		}

+		buf.WriteString(`"attrs":`)

+		buf.Write(mj.RawAttrs)

+	}

 	if first == true {

 		first = false

 	} else {

@@ -21,6 +21,8 @@ func TestJSONLogsMarshalJSONBuf(t *testing.T) {

 		&JSONLogs{Log: []byte("\u2028 \u2029")}: `^{\"log\":\"\\u2028 \\u2029\",\"time\":}$`,

 		&JSONLogs{Log: []byte{0xaF}}:            `^{\"log\":\"\\ufffd\",\"time\":}$`,

 		&JSONLogs{Log: []byte{0x7F}}:            `^{\"log\":\"\x7f\",\"time\":}$`,

+		// with raw attributes

+		&JSONLogs{Log: []byte("A log line"), RawAttrs: []byte(`{"hello":"world","value":1234}`)}: `^{\"log\":\"A log line\",\"attrs\":{\"hello\":\"world\",\"value\":1234},\"time\":}$`,

 	}

 	for jsonLog, expression := range logs {

 		var buf bytes.Buffer